Benthic macrofauna of the intertidal strip of José Menino beach (Santos-SP) Priscila Candido Baroni, Walter Barrella, Roberto Pereira Borges

Abstract

The intertidal region of a sandy beach has a diverse and adapted biota that has a distribution determined by physical factors of the environment.  In these locations, the spatial occurrence of benthic organisms is sensitive to natural and induced changes in the sediments, depending, among other factors, on the beach's exposure to wave action, organic matter content and granulometry. José Menino beach, located in Santos Bay in the central portion of São Paulo's coast, can be subdivided into two sections: to the left and right of the Outfall. The region on the left is marked by the presence of the island of Urubuqueçaba, which allows the formation of three physiognomies of sediment through the action of different water movements and natural deposition as a result of the accumulation of sediment formed by the presence of the island: the left (close to the Emissary), in the center of the island's shadow and to the right of the island. Therefore, the present work aimed to characterize the macrobenthic community in three stretches of José Menino Beach subject to wave action and different sedimentary conditions and correlate the granulometry and organic matter with the observed populations. A higher density of macrofauna individuals (specifically of polychaetes of the species Scolelepis squamata) was observed in physiognomy 2 (in the shadow of the Urubuqueçaba island), and, despite there being no relationship between this occurrence and the granulometric characteristics of the sediment, there is a relationship with organic matter content. The greater density sampled in physiognomy 2 can also be attributed to differences in the movement of water masses, however, a better characterization of environmental variables over time is necessary to establish greater patterns of occurrence of individuals.